Immediately following an acute stroke, it may be necessary to reopen an occluded cerebral blood vessel, preferably within eight hours from the initial occlusion. Manipulation of the endothelium of a cerebral blood vessel is attended by adherence of platelets, which stick to the site of injury, and subsequently release clotting factors that act as chemoattractants, both binding platelets together and provoking more clotting proteins from the blood. The result of this mechanism (platelet aggregation and activation) is the accumulation of platelets and their binding together at the site as a “white thrombus,” i.e. fibrin/platelet thrombus, which rapidly re-occludes the blood vessel. In this situation, a thrombolytic agent such as tPA will no longer be effective, as it has no activity against this different type of thrombus. Thus, conventional methods of removing occlusions in a blood vessel may not be adequate in all situations.